If we had short-answer homework for the analog-digital section, this is what it would look like (so you can study for the exam).
1. violin-wood to air, air to eardrum, air to electricity (microphone), electricity to air (speaker)
2. An A/D converter takes in an analog signal, translating it to a series of digital sample numbers
3. Halve each number: 100, 160, 200, 140, 100
4. 200, 300, 400, 320, 240. The result is lossy